Behavior of Ordinary Load-Bearing Masonry Structure Under Distant Large Explosion, Beirut Scenario

Recent explosion of the stored ammonium nitrate at Beirut port was of devastating nature caused serious damage to the structures to the extent of the collapse of even single-story dwelling houses. This disastrous explosion led to a large number of deaths (≈200) in addition to grievous injuries, and many more. To replicate the effect of devastating explosion on ordinary unreinforced masonry load-bearing residential structure, single-story finite element (FE) dwelling unit model, with the conventional reinforced concrete slab with M20 concrete and Fe500 steel designed to carry the gravity loads, have been developed using the ABAQUS/Explicit program. With the objective to correlate the damage that occurred to similar structures in Beirut, the model is subjected to an explosive load of 2750 tons of Ammonium Nitrate (≈2300 tons of TNT) at standoff distances of 300 and 500 m. The effect of the air-blast pressure has been studied on the load-bearing masonry wall and the supported singly RCC slab of the model under the considered high explosive charge. Concrete-damaged plasticity (CDP) model for concrete and brick masonry available in employed software has been utilized. Damage has been simulated to evaluate the damage dissipation energy and geometric damage parameters of cracks such as average spacing of cracks and their average depth. Macro-modeling has been considered to model the masonry wall and the slab. Stresses have been found out and are compared with those available in the Indian Standard Code of Practice for Structural Use of Unreinforced Masonry, IS 1905: 1987. This research work provides insight into damage to ordinary dwelling structures subjected to explosions produced by a high explosive charge.